En Español

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?


Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

rate this answer
4 ratings

Tuesday - September 28, 2010

From: Georgetown, TX
Region: Southwest
Topic: Trees
Title: Pollenless Cedar Elms for Georgetown, Texas
Answered by: Marilyn Kircus


I am considering planting the Cedar Elm tree at my home in Georgetown, Texas. I was under the impression that only the female of the species produces the irritating pollen. Is this true?


No, pollen is a guy thing.  Pollen contains the male gametes and is analogous to sperm in animals.   Females produce the irritating things known as kids. (For plants, the strategy is to produce them as seeds and not have to incubate them internally for nine months.)  Plants can be him (male) or her (female) or them (both male and female)."Them" kinds of plants can be further divided into those who have both male and female flowers and those who have flowers that contain both male and female parts.  The latter are called bisexual, hermaphroditic or perfect flowers. When flowers of both sexes are on the same plant, it is called monoecious. When the sexes are on two different plants, the species is described as dioecious.

Ulmus crassifolia (Cedar elms) are wonderful shade trees.  They are recommended as a good substitute for oaks since they don’t get oak wilt. I love their yellow fall color. They are used by lots of different wildlife. Their flowers are perfect and are wind pollinated.  They bloom in late summer and fall - usually August to October and their pollen does cause allergies in some people.  Here is more information on them.

So in addition to having perfect flowers, I think it is a pretty perfect tree.

I'm wondering if maybe you are thinking about the pollen problems with Juniperus ashei (Ashe juniper), a.k.a. cedar. These trees ARE dioecious and the cedar pollen is profuse and will travel long distances.  And of course, there are lots of them. This is the pollen that causes the most allergy trouble in central Texas. But it's the guys plants causing the problem.  The girls have the pretty berries.



More Trees Questions

Texas Redbud Suddenly Died in NM
November 06, 2014 - We had a Texas redbud, approximately 5 1/2 years old. It had been doing great then all of a sudden after it bloomed this spring, the leaves appeared but then shriveled right away. We noticed the trunk...
view the full question and answer

Unknown pest of Texas Mountain Laurel from Round Rock TX
May 24, 2012 - I have a Texas Mountain Laurel that is being denuded from the top down by something unseen. It's not the Genista moth larvae, as there are no worms and no webbing visible. The only clue that it might...
view the full question and answer

Having a problem with my Mexican Plum in Houston, TX.
July 05, 2011 - I am having problems with the Mexican Plum Tree in my backyard, sap is oozing from the branches and several large branches have died. I am inclined to think that it I have infestation of borers? How ...
view the full question and answer

Clicking heard under an Oak in near Bandera, TX
May 06, 2014 - Hi, I live on a ranch in TX outside of Bandera. We're covered with live oaks, spanish oak and cedar. Last week,as I stood under an oak, I heard a constant fairly loud clicking sound under and around ...
view the full question and answer

Native trees of Hornsby Bend in Austin, TX
April 10, 2013 - We are looking for a list of the trees occurring along and in the vicinity of the Colorado River at Hornsby Bend circa 1820.
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.
© 2016 Lady Bird Johnson Wildflower Center